The long-term goal of this project is to identify the factors that contribute to the development of hearing in complex acoustic environments. The proposed experiments will characterize child-adult differences in susceptibility to interference from competing background sounds and will identify developmental effects in the ability to use spectral and temporal cues to improve hearing in noise. Recent studies have shown that children are more susceptible than adults to interference from competing sounds. Although the mechanisms that underlie this increased susceptibility are poorly understood, central auditory processes such as sound source determination and selective attention appear to play a major role. Little is currently known, however, about how and when these processes develop. The proposed work has two specific aims. Aim 1 will provide information that can be used to determine the course of development for susceptibility to interference from remote frequency background sounds. Aim 2 will focus on identifying acoustic cues that children rely on to detect target signals in the presence of noise. The results of the proposed studies will enhance our understanding of the factors that limit children's ability to hear in noisy environments. These studies could result in more successful speech and language outcomes for children with hearing loss and could lead to the development of strategies that improve the quality of the acoustic signal in the classroom.